The Effect of Varied Bandwidth, Signal-To-Noise Ratio, and Intensity on the Perception of Consonant-Vowels in a Dichotic Context: Additivity of Central Processing.

Normal subjects were presented simultaneously aligned consonant-vowel stimuli in three forced-choice dichotic experiments in which the information content of one signal was changed by (1) varying the intensity, (2) low-pass filtering, and (3) alterations in signal-to-noise ratios. The results of all three experiments were complementary. As signal characteristics were varied to produce a reduction of information to one ear, and thus a decrement in performance, an increment in performance of the unaltered ear was observed. The trade-off ratios of decrement and increment were such that total performance (summed ear scores) remained virtually constant. Dichotic ear effects (e.g., right ear outperforming left ear) appear to be orthogonal to this phenomenon. These observations indicate that perception of dichotically presented consonant-vowel depends upon the central additivity of information from two quasi-independent channels, overall performance being limited by the capacity of the central processor. [Work supported by NIH.] [ABSTRACT FROM AUTHOR]